Will this tournament only be open to members of already established clans?

Anyone can participate, regardless of clan affiliation! All participants will be ranked at the end.
However, the clan standings will only be calculated among clans that are registered and have three or more participants in this tournament.

Added 4 minutes later

Question - how do I password-protect the archive? Please explain it in detail for me, as I'm not very tech-savvy.

I'll create a help file for WinZip, which will be included in the same archive as the assignment. It will also contain an FAQ about the tournament, including the rules, the map, and instructions on how to install TE – in other words, everything you need.
If there are any difficulties with this format for running the tournament, we can go back to the old method of sending save files via email.
I simply wanted to participate in the tournament myself, and to minimize the number of questions directed at me, I proposed this scheme.
Also, participants are often interested in the save files of their opponents, so they will be available to everyone, and there will be no need to send them back and forth.